SPARK PLUG OF COMPACT STRUCTURE AND MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an especially compact spark plug of a simple structure having same or similar operating mode as compared with conventional ones in, say, conductivity and electric characteristics. SOLUTION: An insulating element (12) and a casing (22) are combined together with a joint of at least one material joint and/or a frictional force joint to the radius direction.